The present invention relates generally to cover folders and more specifically to cover folders for securely holding and covering sheets of paper and a method of constructing the same.
Various kinds of cover folders are utilized to hold papers for business and school reports.
In a cover folder of a well-known type, a sheet of either plastic or paper is folded to form a pair of sheets having a common folded edge. The papers comprising the report are placed between the two sheets with the left side edge of the papers arranged adjacent and parallel to the common folded edge. An elongated plastic or metal binding bar is slid onto the outside of the common folded edge of the cover sheet. Such binders binding bars generally include two elongated panels that are joined along a common edge, the elongated panels forming a narrow opening opposite the common edge through which the cover sheet and the enclosed papers may be inserted. The elongated panels of the binder binding bar resiliently press and hold the opposing leafs of the cover sheet and the enclosed papers together.
A major drawback prevalent in many prior art cover folders of the type described above is that because the binding bar can be readily removed by sliding it either parallel to or at an angle relative to the folded edge. Very often, when the cover sheet is opened and separated, even with only small force, the binding bar tends to move perpendicularly relative to the folded edge. Because there generally is insufficient friction between the binding bar and the cover sheet to keep the binding bar mounted on the common folded edge of the cover sheet, the binding bar may separate from the cover sheet, particularly as the number of pages of the report increases. As a result, the enclosed papers are no longer held together and may become soiled or disorganized if they fall out of the cover sheet.
Due to the relative ineffectiveness of such cover folders, an adhesive or other binding element has often been used in the art to ensure secure engagement. In addition, some report covers comprising a binding bar and a cover have been provided with auxiliary clips or fasteners which must be inserted through the binding bar, the cover, and the sheets of paper held therein. The binding bar may, in any event, be retained to provide additional holding force or to improve the outer appearance of the report cover. The use of auxiliary components for holding the report papers together can result in the need to locate the edges of the pages at a distance away from the folded edge. Accordingly, the overall width of the cover must be increased to provide proper coverage for papers of standard size.
The use of additional clips, fasteners, supports, staples and the provision of additional cover area to properly accommodate the papers necessarily increases the overall cost of the report cover. Also the use of additional fasteners makes it more difficult and time consuming for the user to insert and remove the sheets. Moreover, certain types of report documents may not have sufficient margins for providing holes for the passage of fasteners. Also, it may otherwise be undesirable to form holes in the report pages in order to accommodate the fasteners. Holes are undesirable because, among other things, sheets secured by holes tend to tear during normal handling, and aesthetically, the appearance of such documents are greatly detracted.
As a result, attempts have been made in the art to construct cover folders which do not require an adhesive or other binding element to ensure secure engagement. An example of such a cover folder is disclosed in U.S. Pat. No. 4,486,032 to Leahy, which issued on Dec. 4, 1984. In this patent, there is disclosed a cover folder having a binder that securely retains the cover and inserted sheets, without the use of external fasteners. The cover is formed from a sheet which is folded once and then folded again to form the overlapping flap formed on the cover sheet. The binder is an elongated bar with an interior channel for receiving and holding a folded cover. The bar includes within the channel slanted ribs which engage the folded edge of the cover sheet along an overlapping flap. The overlapping flap of the cover sheet may be made more rigid by heat treatment and/or by a reinforcing coating.
Another report cover is disclosed in U.S. Pat. No. 4,575,123 to Giblin et al, which issued on Mar. 11, 1986. In this patent, a folded report cover is provided with a lock strip extending along at least one side of the cover parallel and contiguous to the fold and outwardly of the plane of the side. A channel-shaped gripping member is engaged to the cover along the fold and locked in place by a stop which extends from the interior of one leg of the gripping member into resilient engagement with a longitudinal edge of the lock strip and the one side of the cover. The other leg of the gripping member engages the opposite side of the cover. The lock strip is preferably an integral portion of the material of the cover.
Other examples include U.S. Pat. No. 5,226,676 to K. J. Su, U.S. Pat. No. 4,934,738 to R. Colonna, U.S. Pat. No. 4,904,104 to F. Gloeckle, U.S. Pat. No. 4,867,479 to S. Mizutani, U.S. Pat. No. 4,682,792 to G. Simmons, U.S. Pat. No. 4,521,035 to J. W. Berezowsky, U.S. Pat. No. 4,402,530 to G. Daguerre, U.S. Pat. No. 4,351,546 to C. Cognata, U.S. Pat. No. 2,349,947 to H. Einzig, U.S. Pat. No. 990,262 to G. H. Hedges, and U.S. Pat. No. 936,223 to J. N. Dean.